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XII. 

 GEOLOGICAL SURVEY OF INDIA. 



From a geological point of view, India is most conveniently 

 regarded as presenting a threefold aspect, and this is the general 

 division of the country adopted in the " Manual of the Geology of 

 India," i.e., into the peninsular area, the extra-peninsular area, and 

 the great Indo-Gangetic alluvial plain separating the two. 



When we proceed to distinguish the various formations, we find 

 that the geology of the country south of the Himalayas presents a 

 comparatively simple aspect, in that all the rocks are easily 

 separated into the following great groups, viz. : — 

 6. Alluvial plains. 



5. Sedimentary rocks, of Jurassic, cretaceous, and tertiary ages. 

 4. The Deccan basalt, of cretaceous and lower tertiary age. 

 3. The Gondwana system, comprising the Indian coal measures, 

 and ranging inclusively from the age of the English coal 

 measures to that of the Portland and Purbeck beds. 

 2. The Yindhyan system, a formation peculiar to India, the ago 

 of which cannot be guessed, as it has yielded no fossils, 

 but which is immensely older than the Gondwanas. 

 1. The archaean or metamorphic rocks, such as gneiss and 

 crystalline schists with the granite often occurring in them, 

 and with some slaty rocks that have partially escaped the 

 general metamorphism.* 



Long before the establishment of an organised geological survey, 

 a series of travellers had from time to time recorded observations 

 of a practical or scientific character on the rocks and minerals of 

 India. Foremost among these observers were Dr. Falconer and Sir 

 Proby Cautley, to whom the discovery of the wonderful fossil fauna 



* A detailed consideration of these formations does not come into the province of 

 this book. It may be mentioned, however, (hat an excellent and picturesque general 

 account of the Geology of India, from the pen of .Mr. Medlicott, F.R.S., late Director 

 of the Survey, is to be found in Sir Edward Buck's Statistical Atlas of India, while 

 those who desire to pursue their investigations still further should consult the Manual 

 of the Geology of India, in 4 vols, with map, Calcutta and London (Trubner). 



